Below is a transcript of an IMAP-over-openssl session grabbed while no other MUA was running.
### grab a message and note that it has only the Seen flag
a fetch 353 (flags BODY[HEADER.FIELDS (SUBJECT)])
* 353 FETCH (FLAGS (\Seen) BODY[HEADER.FIELDS (SUBJECT)] {34}
Subject: Christmas Party notes
)
a OK Fetch completed.
### Now add the "social" flag to the same message
a store 353 +flags social
* 353 FETCH (FLAGS (\Seen social))
a OK Store completed.
### Fetch the newly-modified message to see that the change stuck!
a fetch 353 (flags BODY[HEADER.FIELDS (SUBJECT)])
* 353 FETCH (FLAGS (\Seen social) BODY[HEADER.FIELDS (SUBJECT)] {34}
Subject: Christmas Party notes
)
a OK Fetch completed.
### but after a couple of fetches, the new flag disappears :-(
a fetch 353 (flags BODY[HEADER.FIELDS (SUBJECT)])
* 353 FETCH (FLAGS (\Seen social) BODY[HEADER.FIELDS (SUBJECT)] {34}
Subject: Christmas Party notes
)
* 353 FETCH (FLAGS (\Seen))
a OK Fetch completed.
a fetch 353 (flags BODY[HEADER.FIELDS (SUBJECT)])
* 353 FETCH (FLAGS (\Seen) BODY[HEADER.FIELDS (SUBJECT)] {34}
Subject: Christmas Party notes
)
a OK Fetch completed.
QUIT
I encountered this problem thinking Thunderbird was somehow losing or failing to store tags, but blame seems to lie with the server.
Is this a defect in the IMAP server software (at rackspace.com: secure.emailsrvr.com), or am I understanding the IMAP definition incorrectly?
UPDATE: Based on the following, Rackspace seems to be running the Dovecot IMAP server:
- Creator of Dovecot Joins Mailtrust
- Rackspace sponsorship of Dovecot development
- First slide of Dovecot talk
Dovecot losing tags while running with the mbox_lazy_writes option is a known issue in Thunderbird's bug tracker (see also), but I have no way of knowing whether that's the active configuration.
